In the Last Major Crisis Between the United States and Britain

In the last major crisis between the United States and Britain during the Civil War,war was prevented when the British agreed

A) not to trade with the Confederacy.
B) to remove their warships from the St Lawrence River.
C) to end their intrigues in Mexico.
D) to cede territory in lower Canada.
E) not to sell the Laird rams to the Confederacy.